1. Field of the Invention
The present invention relates to an air conditioning system suitable for use in an electric vehicle, and more specifically to such an air conditioning system wherein the inside of the vehicle can be air-conditioned by an external drive source before the vehicle runs and a comfortable room environment can be obtained upon riding by detecting a clear state of a piece of front or rear window glass with a sensor and energizing a glass temperature-increasing means until the front or rear glass is brought to a clear state.
2. Description of the Related Art
The concept of mounting an air conditioner in a vehicle and controlling the temperature, humidity, airflow, etc. inside of the vehicle so as to ensure a comfortable room environment, has heretofore been effected.
However, in a vehicle provided with an internal combustion engine in particular, when the internal combustion engine is in a non-driven state, the air conditioner cannot be activated. Therefore, when a driver or a passenger rides in the vehicle, the driver or passenger feels displeasure due to a high temperature or humidity, for example. It is also difficult to achieve the comfortable room environment quickly because the operation of the air conditioner should be delayed until the engine exhibits normal power or the warm or cold air should be supplied to the inside of the vehicle at a reduced rate of airflow, for example.
In order to overcome such inconvenience, a "vehicle room environment control apparatus" has been proposed in Japanese Laid-Open Patent Publication No. 3-2325, for example. According to the proposal, the control apparatus detects the temperature or the like inside of the vehicle in advance. Then, the engine is automatically started before the driver rides in the vehicle to thereby adjust the temperature, humidity, etc. in the vehicle room.
In such a control apparatus, however, the engine may be driven over a long period of time in an unmanned state. Therefore, ambient conditions are contaminated with gas exhausted from the engine and noise produced therefrom. Further, since the operation starting time of the air conditioner cannot be changed in response to increased temperature conditions, the vehicle room cannot be brought to a comfortable temperature at the riding time owing to the fact that the operation starting time is too late. Alternatively, in lower temperature conditions, the air conditioner is activated and operates beyond the need owing to the fact that the operation starting time is too early.
A similar system is disclosed in U.S. Pat. No. 4,436,064 for use with a vehicle having an internal combustion engine for starting the engine and heating the vehicle room in advance of a selected time for riding in the vehicle based on actual temperature conditions sensed by the system.
Additional problems occur if the vehicle to be used is an electric vehicle. When an air conditioner of the electric vehicle is activated before a driver rides in the electric vehicle, a part of the current required to charge the battery which serves as a drive source used for running the vehicle, is supplied to the drive source of the air conditioner. Consequently, there is often a situation in which the charging current of the battery runs short.
On the other hand, if the vehicle is provided with a warm air supplying means such as a heater, a defroster or the like to avoid a dimmed or iced state from being developed on the front or rear window glass or the like. Various proposals have heretofore been made to automatically remove the dimness or icing from the front or rear window glass.
For example, a dimness detector employed in a vehicle has been disclosed in Japanese Patent Application Laid-Open Publication No. 2-304343. In the dimness detector, a sensor comprised of an electrolytic single crystal and a resistance detecting means for detecting the resistance of the sensor are disposed on the inner surface of the window glass. It is then determined based on the resistance value detected by the resistance detecting means whether or not the window glass is in a dimmed or unclear state. A defroster mechanism is thereafter activated based on the result of determination.
Further, a dimness detecting apparatus has been disclosed in Japanese Patent Publication No. 3-36180. The dimness detecting apparatus has a light-transmitting device, a light-receiving device, and a detecting circuit for comparing a signal outputted from the light-receiving device and a reference value to thereby output a dimness detection signal based on the result of its comparison. In this dimness detecting apparatus, the light-transmitting device and the light-receiving device are symmetrically mounted relative to the front or rear window. Thereafter, a defroster mechanism is automatically activated in response to the signal outputted from the detecting circuit.
In the above disclosures, the dimness detector and the dimness detecting apparatus are activated after the vehicle has run. When the front window glass is iced in winter or when water or moisture is condensed on the front or rear window glass during the rainy season, for example, the driver makes use of a mechanical means, such as a scraper, windshield wipers or the like, so as to remove ice formed on the front or rear window glass or to wipe off the water or moisture condensed on the front or rear window glass before making an immediate start in the running. Thus, the above-described operations are troublesome to the driver before the running of the vehicle. Moreover, a lot of time is spent before the running of the vehicle.